ng_ipfw.c revision 230214 
1121054Semax/*-
2121054Semax * Copyright 2005, Gleb Smirnoff <glebius@FreeBSD.org>
3121054Semax * All rights reserved.
4121054Semax *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/sys/netgraph/ng_ipfw.c 230214 2012-01-16 12:33:55Z glebius $
27 */
28
29#include "opt_inet.h"
30#include "opt_inet6.h"
31
32#include <sys/param.h>
33#include <sys/systm.h>
34#include <sys/kernel.h>
35#include <sys/lock.h>
36#include <sys/mbuf.h>
37#include <sys/malloc.h>
38#include <sys/ctype.h>
39#include <sys/errno.h>
40#include <sys/rwlock.h>
41#include <sys/socket.h>
42#include <sys/syslog.h>
43
44#include <net/if.h>
45
46#include <netinet/in.h>
47#include <netinet/in_systm.h>
48#include <netinet/in_var.h>
49#include <netinet/ip_var.h>
50#include <netinet/ip_fw.h>
51#include <netinet/ipfw/ip_fw_private.h>
52#include <netinet/ip.h>
53#include <netinet/ip6.h>
54#include <netinet6/ip6_var.h>
55
56#include <netgraph/ng_message.h>
57#include <netgraph/ng_parse.h>
58#include <netgraph/ng_ipfw.h>
59#include <netgraph/netgraph.h>
60
61static int		ng_ipfw_mod_event(module_t mod, int event, void *data);
62static ng_constructor_t	ng_ipfw_constructor;
63static ng_shutdown_t	ng_ipfw_shutdown;
64static ng_newhook_t	ng_ipfw_newhook;
65static ng_connect_t	ng_ipfw_connect;
66static ng_findhook_t	ng_ipfw_findhook;
67static ng_rcvdata_t	ng_ipfw_rcvdata;
68static ng_disconnect_t	ng_ipfw_disconnect;
69
70static hook_p		ng_ipfw_findhook1(node_p, u_int16_t );
71static int		ng_ipfw_input(struct mbuf **, int, struct ip_fw_args *,
72			    int);
73
74/* We have only one node */
75static node_p	fw_node;
76
77/* Netgraph node type descriptor */
78static struct ng_type ng_ipfw_typestruct = {
79	.version =	NG_ABI_VERSION,
80	.name =		NG_IPFW_NODE_TYPE,
81	.mod_event =	ng_ipfw_mod_event,
82	.constructor =	ng_ipfw_constructor,
83	.shutdown =	ng_ipfw_shutdown,
84	.newhook =	ng_ipfw_newhook,
85	.connect =	ng_ipfw_connect,
86	.findhook =	ng_ipfw_findhook,
87	.rcvdata =	ng_ipfw_rcvdata,
88	.disconnect =	ng_ipfw_disconnect,
89};
90NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct);
91MODULE_DEPEND(ng_ipfw, ipfw, 2, 2, 2);
92
93/* Information we store for each hook */
94struct ng_ipfw_hook_priv {
95        hook_p		hook;
96	u_int16_t	rulenum;
97};
98typedef struct ng_ipfw_hook_priv *hpriv_p;
99
100static int
101ng_ipfw_mod_event(module_t mod, int event, void *data)
102{
103	int error = 0;
104
105	switch (event) {
106	case MOD_LOAD:
107
108		if (ng_ipfw_input_p != NULL) {
109			error = EEXIST;
110			break;
111		}
112
113		/* Setup node without any private data */
114		if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node))
115		    != 0) {
116			log(LOG_ERR, "%s: can't create ng_ipfw node", __func__);
117                	break;
118		};
119
120		/* Try to name node */
121		if (ng_name_node(fw_node, "ipfw") != 0)
122			log(LOG_WARNING, "%s: failed to name node \"ipfw\"",
123			    __func__);
124
125		/* Register hook */
126		ng_ipfw_input_p = ng_ipfw_input;
127		break;
128
129	case MOD_UNLOAD:
130		 /*
131		  * This won't happen if a node exists.
132		  * ng_ipfw_input_p is already cleared.
133		  */
134		break;
135
136	default:
137		error = EOPNOTSUPP;
138		break;
139	}
140
141	return (error);
142}
143
144static int
145ng_ipfw_constructor(node_p node)
146{
147	return (EINVAL);	/* Only one node */
148}
149
150static int
151ng_ipfw_newhook(node_p node, hook_p hook, const char *name)
152{
153	hpriv_p	hpriv;
154	u_int16_t rulenum;
155	const char *cp;
156	char *endptr;
157
158	/* Protect from leading zero */
159	if (name[0] == '0' && name[1] != '\0')
160		return (EINVAL);
161
162	/* Check that name contains only digits */
163	for (cp = name; *cp != '\0'; cp++)
164		if (!isdigit(*cp))
165			return (EINVAL);
166
167	/* Convert it to integer */
168	rulenum = (u_int16_t)strtol(name, &endptr, 10);
169	if (*endptr != '\0')
170		return (EINVAL);
171
172	/* Allocate memory for this hook's private data */
173	hpriv = malloc(sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO);
174	if (hpriv== NULL)
175		return (ENOMEM);
176
177	hpriv->hook = hook;
178	hpriv->rulenum = rulenum;
179
180	NG_HOOK_SET_PRIVATE(hook, hpriv);
181
182	return(0);
183}
184
185/*
186 * Set hooks into queueing mode, to avoid recursion between
187 * netgraph layer and ip_{input,output}.
188 */
189static int
190ng_ipfw_connect(hook_p hook)
191{
192	NG_HOOK_FORCE_QUEUE(hook);
193	return (0);
194}
195
196/* Look up hook by name */
197static hook_p
198ng_ipfw_findhook(node_p node, const char *name)
199{
200	u_int16_t n;	/* numeric representation of hook */
201	char *endptr;
202
203	n = (u_int16_t)strtol(name, &endptr, 10);
204	if (*endptr != '\0')
205		return NULL;
206	return ng_ipfw_findhook1(node, n);
207}
208
209/* Look up hook by rule number */
210static hook_p
211ng_ipfw_findhook1(node_p node, u_int16_t rulenum)
212{
213	hook_p	hook;
214	hpriv_p	hpriv;
215
216	LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
217		hpriv = NG_HOOK_PRIVATE(hook);
218		if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum))
219                        return (hook);
220	}
221
222	return (NULL);
223}
224
225
226static int
227ng_ipfw_rcvdata(hook_p hook, item_p item)
228{
229	struct m_tag *tag;
230	struct ipfw_rule_ref *r;
231	struct mbuf *m;
232	struct ip *ip;
233
234	NGI_GET_M(item, m);
235	NG_FREE_ITEM(item);
236
237	tag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL);
238	if (tag == NULL) {
239		NG_FREE_M(m);
240		return (EINVAL);	/* XXX: find smth better */
241	};
242
243	if (m->m_len < sizeof(struct ip) &&
244	    (m = m_pullup(m, sizeof(struct ip))) == NULL)
245		return (ENOBUFS);
246
247	ip = mtod(m, struct ip *);
248
249	r = (struct ipfw_rule_ref *)(tag + 1);
250	if (r->info & IPFW_INFO_IN) {
251		switch (ip->ip_v) {
252#ifdef INET
253		case IPVERSION:
254			ip_input(m);
255			return (0);
256#endif
257#ifdef INET6
258		case IPV6_VERSION >> 4:
259			ip6_input(m);
260			return (0);
261#endif
262		}
263	} else {
264		switch (ip->ip_v) {
265#ifdef INET
266		case IPVERSION:
267			SET_HOST_IPLEN(ip);
268			return (ip_output(m, NULL, NULL, IP_FORWARDING,
269			    NULL, NULL));
270#endif
271#ifdef INET6
272		case IPV6_VERSION >> 4:
273			return (ip6_output(m, NULL, NULL, 0, NULL,
274			    NULL, NULL));
275#endif
276		}
277	}
278
279	/* unknown IP protocol version */
280	NG_FREE_M(m);
281	return (EPROTONOSUPPORT);
282}
283
284static int
285ng_ipfw_input(struct mbuf **m0, int dir, struct ip_fw_args *fwa, int tee)
286{
287	struct mbuf *m;
288	struct ip *ip;
289	hook_p	hook;
290	int error = 0;
291
292	/*
293	 * Node must be loaded and corresponding hook must be present.
294	 */
295	if (fw_node == NULL ||
296	   (hook = ng_ipfw_findhook1(fw_node, fwa->rule.info)) == NULL)
297		return (ESRCH);		/* no hook associated with this rule */
298
299	/*
300	 * We have two modes: in normal mode we add a tag to packet, which is
301	 * important to return packet back to IP stack. In tee mode we make
302	 * a copy of a packet and forward it into netgraph without a tag.
303	 */
304	if (tee == 0) {
305		struct m_tag *tag;
306		struct ipfw_rule_ref *r;
307		m = *m0;
308		*m0 = NULL;	/* it belongs now to netgraph */
309
310		tag = m_tag_alloc(MTAG_IPFW_RULE, 0, sizeof(*r),
311			M_NOWAIT|M_ZERO);
312		if (tag == NULL) {
313			m_freem(m);
314			return (ENOMEM);
315		}
316		r = (struct ipfw_rule_ref *)(tag + 1);
317		*r = fwa->rule;
318		r->info &= IPFW_ONEPASS;  /* keep this info */
319		r->info |= dir ? IPFW_INFO_IN : IPFW_INFO_OUT;
320		m_tag_prepend(m, tag);
321
322	} else
323		if ((m = m_dup(*m0, M_DONTWAIT)) == NULL)
324			return (ENOMEM);	/* which is ignored */
325
326	if (m->m_len < sizeof(struct ip) &&
327	    (m = m_pullup(m, sizeof(struct ip))) == NULL)
328		return (EINVAL);
329
330	ip = mtod(m, struct ip *);
331
332	NG_SEND_DATA_ONLY(error, hook, m);
333
334	return (error);
335}
336
337static int
338ng_ipfw_shutdown(node_p node)
339{
340
341	/*
342	 * After our single node has been removed,
343	 * the only thing that can be done is
344	 * 'kldunload ng_ipfw.ko'
345	 */
346	ng_ipfw_input_p = NULL;
347	NG_NODE_UNREF(node);
348	return (0);
349}
350
351static int
352ng_ipfw_disconnect(hook_p hook)
353{
354	const hpriv_p hpriv = NG_HOOK_PRIVATE(hook);
355
356	free(hpriv, M_NETGRAPH);
357	NG_HOOK_SET_PRIVATE(hook, NULL);
358
359	return (0);
360}
361